Micrometer



Dec. 18, 1928.

G.N. KoHLHAAs MICROMETER Filed March 4. 1927 Patented Dec. is, 192e.

UNITI-:o TATE-s GEORGE N. xoHLHAAs,

or rinunzia-.NEW YORK.

MICRQMETER.

Appiication nica March 4, i927. serial mirages.

The invention relates to improvements in i micrometer gages of the type adapted to measure to a high degree of accuracy, the in'- terior diameter of metal tubes and bores.

An object of the present invention is to provide a device adapted to be used for measuring in two different ways whereby it is capa- 'ble of measuring tube and boring diameters of widely varying size. l

Another object is to provide a micrometer by Which measurements may be taken either at the mouth of a tube, or boring, or at a considerable distance within said tube.

A further object is to provide for use with the micrometer device properof a series of interchangeablepin members for measuring diameters up to a certain length, and a series of extensions for measuring diameters beyond the said certain diameter.

The invention comprises the features, com-4 bination, and arrangement of parts hereinafter'described and particularly pointed out in the claims.

. In the drawings o Fig. 1 is a sectional view ofthe micrometer, and Y Fi 2 is a side elevation ofthe same with'a hand ev extension attached.

Fig. 3 Ishows the micrometer in measuring position with its ends used as contacts.l

. Fig. 4 is a view of a detail ofthe invention. Fig. 5 shows the quadruple thread on the handle 7 and sleeve 2. Referring by reference characters. to the figures, the letter A in Fig. 1 indicates the end of a tube, the diameter of which is to-be measured, as does also the letter B inv Fig. 3.--

The measurement ofthe diameteriof A in Fig'.l 1 is'accomplishedby means of pins 4: which are guided as hereinafter described in a head 6 and are forced outward to causev their.

outer ends to contact with the inner wall of thetube, b a cone 10, which is moved longi- "tudinallyj y screw 'means hereinafter described. The head 6 isfcarried at the .end of a tubular body 3 forward and the forward end of the head is of conical shape as shown at 11,'and provides an internal recess to receive the cone 10. The pins 4 passthrough openings in the body 3 and bear at the front in radial grooves of semi-circular cross-section -in the enlarged portion or flange of the head 6'. I A movable washer9encircles the plain portion of the body 3 and coacts with the head 6 in holdin the pins in place, the washer being provi ed with pin engaging radial.

grooves corresponding to those in the head..

tion of the body 3 in rear of the washer. 9 and presses the washer up against the pins 4. The spring is compressed between the washer 9 and a combination lock nut and thimble 1 which is threaded onto tubular body3. .The

combination lock nut and thimble 1 has a recessed portion so that it overlaps the spring and excludes dirt, this overlapping portion overlapping a small fiange 'of the washer 9.

The lock nut 1 is adapted to be screwed up against the washer 9 so as to force the latter tightly against the pins to'hold them fromv slipping out, but not toclamp them against v radial movement such, as is imparted by the cone 10. The memberl and washer 9 are provided with marks l19 adapted to register with each other so that the member 1 will always be tightened to the same amount `before taking a reading, since the member' 1 is- A helical spring 8 encircles the plain porthe micrometer thimble as well asa lock nut,`

and sp must be always established in the same l so position before accurate readings can be obtained by movement of the barrel 2, herein- 1 after' described, relative thereto.

If it is desired to replace the pins 4 by a `different set, the member 1 is slightlyfunv screwed, which relieves the washer 9 from the strong clamping action of the member 1, but yet leaves, the spring 8 sufficiently compressed to exert enough pressureon the washer 9 to keep the pins from dropping out, although they may bere'adily removed and replaced by hand.

The tubular body is threaded internally yand externally in rear of the spring abutment on the member 1 the inner'threads engagecorresponding threads on the screw threaded lstem 5, which carries the cone 10. The external threads engage corresponding threads on the member 1 and on a. barrel memvber2.l The barrel member, is secured to the ,screw 5, as hereinafter described,.and carries the screw 5 forward`or backward-as the'barrel is screwedforward or backward on the body v 3. The barrel 2` is secured to screw 5 by having reverse or left hand spiral quadruple than? threadsin its rear end which engage correlll spending reverse threads formed on a nut 7 which is screwed onto the -screw 5 adjacent its rear end and is locked in position by lock nut 1d, and the barrel 2 is then screwed up on the nut T until it abuts a knurled handle 7 integral with the nut 7 at its rear end.

This arrangementfprovides a locking feature, the barrel 2v also acting as a lock nut in conjunction with the lrnurled handle 7' which for purposes'of operation may be regarded as integral with screw 5. The barrel 2 having'b-oth right and left hand threads thereon, the instrument can readily be locked by holding the barrel with one hand and turning the handle f Z clockwise with the other. This loclrs the' quadruple threads of the screw .memberf against the quadruple threads of the barrel 2 and locks the right hand threads of' barrel 2 and the right hand threads of screw against the threads of the'- body 3, thus loclring the whole instrument.. The reason for this locking action is thev opposition of the quadrupleth'read action to that of the right hand threads, thus locking all of the threads. To release, the head and pins are held with Vone hand, and the handle turned -anti-cloclrwise with the other. The "rotary, movement of handle 7 relative to the barrel 2 is very slight, there being but a very small are traveled between locked and unlocked position. 'The locked position locks'the instrument, but the unlocked position` locks the handle 7 and barrel2 together suiiiciently 5' to permit rotation of the barrel by the handle.

Y The uadruple thread will lock the instrua simple twisting motion.

ture of the right and left hand combinationA ment rmly enough for all practicalpurposes, but not so firmly that it cannot be released by The locking feabarrel and loclrnut also serves the purpose of taking care of wear in the micrometer by eliminating parts. l

The barrel 2 has a line 12 thereon with l graduations thereon running from zero upward toward the rear end The rearward' which are suita ly numbered around its pei riphery. 1n operation., if it is desired to de termine the interior diameter of the tube L shown in Fig. 1, a suitable set of vpins 4 is inserted, andthe thimble 1 is turned up against the washer 9 untilthe correspoiuling marks coincide, lf loclred, the device is unlocked by turning the handle 7 counter clockwise l.

and then the barrel 2 may be readily turned cloclrwise by the handle or by itself until the pins 4 are extended to contact with the inner periphery of the tube, when the instrument may be 'locl'red in position and a reading talren. For measuringI the diameter at a the instrument as contact members.

v the other contact.

the necessity ofreadjustment of' considerable distance within the tube a han i at. rlhe locking feature is especially useful in this case since the instrument may be locked in set position before insertion and thus eliminate liability of the setting being changed either in insertion or removal.

The measurement of the diameter of B in Fig. 3 is accomplished by using theends of The rounded end of the cone 11 serves as one contact and a cap 14, Fig. 3, is screwed onto the other end of the instrument and serves as A series of extensions of varying lengths, such as shown in Fig. 2, is used in connection with the instrument for measuring widely varying diameters.

,In the use of the instrument'. in this way thediameter ofthe tube at the/mouth may be measured by holding the instrument diametrically across the mouth of the tube, and

turning the barrel 2, to which Contact cap 14 is attached, relative to the thimble 1 to which the other contact is connected, until the contacts engage the inner periphery of the tube. r

end of the micrometer in forming the coupling. The cap 14 is then screwed upon the free end of the extension. Obviously one or ,more extensions may-be added one to the other by means of collar 15.

One of the coupling collars 15 isof the form yshown at 17 in Fig'. 4 and has a rounded plug 16 screwedvin it and having two flat sides. By means of the screw plugl the length of the micrometer may be adjusted to compensate forany wear which may take place between the threadedly connected parts of the micrometer proper, or in its end contacts orin its extension connections, so that accuracy of lreadings may be assuredat all timeswhen the ends of the instrument are used as contact members.- The screw plug 16 is adapted to be usedas a contact point in place of cap 14. It will be readily seen that by employing a number of sets ofpins 4 and a series of eXtensions,` any diameter up to two feet vor more` may be accurately measured. -The nut 7v being screwed upon the screw 5 and locked to take care of any wearwhich l may take place'in the operative threadedly .connected arts of thel'micrometei-,f-s-o.that

accuracy o readings of diameterslmay at all s radial. guide grooves thereon, a washerhav#l f ing cor-responding guide grooves Aopposing said first mentioned grooves, pins guided in said grooves, means for pressing the washerv against the pins, said means comprisinga combination lock nut and micrometer thimble, and lmeans forA forcing the pins outwardly.

times be assured. I claim:

tubular body portion lhaving va-"head with ,2. Incombination, an interiorly and exte riorlythreaded tube, radially arranged pins.Y

at theforward'end thereof,- a cone extending between said pins and havinga threaded stem extending-rearwardly throughthe-tube in threaded engagement therewith andv to a point beyond the opposite end thereof, an interiorly threaded barrel connected to the rear end of said stem vand vhaving its interior threads engaged by the exterior threads of said tube, and an interiorly threaded thimble f having its interior threads engaged -by the exterior threads of said tube. said thimble extending rearwardly beyond. its threaded portion-to overlie the said barrel, saidbarrel and -the rearward end of said thimble being -provided with graduations.

3. In combination, in a micrometer gage, an interiorly and exteriorly threaded tube, radially` movable pins lat the-forward end thereof, a cone extending between said pins and having a threaded stem engaging the interior threads of-'said tube and extending rearwardly through the tube and to a point beyond the opposite end thereof, an interiorly `threaded barrel receiving saidstem and connected at its rear end to the rear end of the stem whereby said' .barrel vextends forwardly v overthe st em from its connection therewith,

the intriorthreads at the forward end; of

i the barrel engaging the threaded rear endof the tube, andan interiorly threaded thimble having its interior threads engaged by the exterior threads of said'tube, said thimble extending rearwardly beyond its threaded por- 'I tion to ovefrlie` said barrel.

' 4. In combination, an interiorlyand exte;v

" riorly threaded tube, radially movable pins at the forwardend thereof, a cone extendingl between said pins and havinga threaded stem l engaging the interior threads of said'tubefan'd .extending rearwardly through said tube and to'a` point beyond the opposite end thereof, "said stem-having-an enlargement at its rearl end provided with a lefthand quadruple.

thread, and a second enlargement beyond and rising from the first and forming a vknurled Y lhandle', an interiorly threaded combination f barrel and lock nut being vthreaded at its'forward end toengage the exterior threads of said tube andfhaving at its rear end a left hand quadruple thread to engage the quading a'stopfor said combination barrel Vand v die being capable lof slight turning movement `relative to 'the' lock nut vvwhen theloc'knut is in engagement with'the threads, on the, tube,

locknut when the latter is'screwed on tothe v w l stem by `the quadruple thread, and said han- 1. In ,combination in amicrom'eter gage, a

Sto lock thevst'em and llockruit-'againstl move-Y ment, ana aniateririy threaded ambie hav- .ingits threads engaged by the exterior -threads of said tube, said thimble extending l. rearwardly'beyond its threaded portion to overlie. said ,combinationbarrel and lock nut.

' 5.--In combination -in` a micrometer gage, a

tube, radially arranged pins at the forwardv end thereof,=a cone extending between said pms and having .athreaded stem extending rearwardly through and beyond said tube tov vengage- With aoombi'nation' micrometer barrel and lock nut'whereby the stem and barrel may be locked together and against turning, and a combination micrometer thimble and pin lock nut adapted to hold the pins in radially movable position, and to cooperate with said micrometer barrel.

6. In combination, a tubular body portion having at its forward end .a flanged head with semi-circular recesses in said head, a

washer having corresponding semicrcular recessesopposing said first mentioned recesses, pins'guided in said recesses, said tubular "body f being interiorly and exteriorly threaded, a oo ne extending between said pins and having a'threaded stem engaging the'interior threads of sai-d tube and extending rearwardly througlrand beyond said tube, anv interiorly threaded barrel receiving said stem and connected `atitsre'ar end to the rear end of the stem whereby said barrel extends forwardly over the stem fromits con-v .nection therewith', theinterior threads at the forward'end of thel barrel engaging the threaded rear end of the tube, an interiorly threadedcombinati'on lock nut and thimble im Y Y threads .of saidtube, saidy thimble extending i `rearwardly 'beyond its threaded porticato overliel saidbarrehsaid combination locknut l andthimblehavingaportion extending for- Wardly from itsthreaded portion and proa viding a Arecess between it'and said tube, ar spring in said vrecess,between said lock nut' :ff 'and'said washer,s'aid forwardly extending having itsr threads engaged by theexterior 'portion' .of said locki nutbeing adapted to engage said washer to hold the pins in rais disengaged fromfsaid 'vv/asher.'l

'a tubular body portion having at its forward -dially'movable position,.. said spring beingY l' adapted to ihold said-pins when'the lock nut i end aflanged head with semiecirlcular re cesses in sai-d head awasherhaving-corre spending semi-circular yrecesses, opposing vsaid first mentioned recesses, pinsguided in said recesses, said -tubular body being teriorly and exteriorly threaded, a cone extending between said pins and having a threaded stem engaging the interior threads with a left handv quadruple thre'ad, and a seoond enlargement beyond and rising from the first and forming a knurled handlefan interiorly threaded combination barrel and' lock nut being threaded at its forward end to engage the exterior threads of said tube and having at its rear end a left handquadruple thread to engage/the quadruple thread of the stem, -said handle forming a stop for said combination barrel and lock nut when the latter is screwed onto the stem by the quadruple thread, said handle being capable of slight turning movement relative to said combination barrel and loclrnut,'when the same is in engagement with the threads on the tube, to lock the stem and barrel against movement, an interiorly threaded combination pin lock nut and thimble having its threads engaged by the exterior threads of said tube, sai-d thimble extending rearwardly beyond its threaded portion to overlie said barrel, said combination lock nut and thimble having a portion extending forwardly from its threaded portion and providing a recess between it and said tube, a s ring in4 said recess between -said thimble an said washer, the forwardly extending portion of said thimble being adapted to engage said washerv .to hold the pins in radially movable position, Said spring being adapted to hold said pins, when the lock nut is disengaged from said washer.

A 8. In combination in a micrometer gage, a tube, radially movable measuring pins mounted at one end of said tube, means for actuating said pins, locking means for holding said pins in radially movable position,

comprising a micrometer thimble, and locking means for means vfrom moving.v

9. In combination in a micrometer gage,

preventing the pin actuating a cap adapted to be screwed upon said threaded end,.a series of extension members having their ends threaded and coupling collars for connecting said extension members with themselves, or with said stem', whereby the length of the micrometer can be adjusted by the insertion or removal of one or more extensions between the threaded end of the stem and the said cap.

10. In combination in a micrometer gage, A.

a tube, radially removable pinsatthe forward end thereof, a cone extending between said pins and having a stem exten-ding rearwardly through and beyond said tube in threaded engagement therewith, said stem having at its rear end a left-handed threaded portion, a barrel having a left-handed'thread at itsrear end in engagement with the left. handed thread on the stem and having a thread at its forward end in threaded engagement with the exterior o'f the tube, and a thimble securedlto said tube and adapted to cooperate with said barrel.

1l. In a device according to claim .10, said stem, when screwed into the barrel tothe limit of the left-handed thread/ being adapted to permit relative screw turning movement between the stemV and barrel as one unit and t-he tube and thimble as the other unit of the micrometer, and said stem being also adapted, whenslightly unscrewed` from the barrel, to lock` the whole instrument. I

In testimony whereof I aiix my signature.

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